The present invention relates to an arrangement for a towing vehicle in for a strengthened coupled connection with a towed vehicle and paticularly concerns a support contrivance or assembly connected to the frame side members of the vehicle and including a beam arragement.
Towing vehicles include in many cases a support contrivance arranged between two substantially parallel frame side-members to prevent sideways movement of the latter. When the towing vehicle is coupled to a trailer, laterally directed forces occur, for example, on bends, thereby causing a bending moment on the frame side-members. Such a support contrivance may take the form of a so-called cross-stay, i.e. two members or rods which extend in a substantially horizontal plane diagonally between the frame side-members in such a way as to cross one another.
In some cases it may be difficult to fit such a support contrivance, e.g. where the towing vehicle has its drive engine in the rear end of the vehicle or has a cargo space at the rear end between the frame side-members. Modem buses often have the drive engine at the rear end for the sake of such advantages as more space in the forward parts of the bus to facilitate boarding. The drive engine thus hinders the fitting of a cross-stay or some similar support contrivance which extends between the frame side-members. The drive engine itself is usually mounted on the frame side-members but performs no supporting function, since it is mounted on resilient rubber cushions.
On certain markets it is also usual to use also towing vehicles such as buses, i.e. to have the towing vehicle carry passengers. Such towing vehicles do of necessity become relatively heavy, thereby further accentuating the problem indicated above. It would of course also be desirable to be able to use buses with the drive engine in the rear end as such towing vehicles.
The object of the present invention is to provide an arrangement for a towing vehicle whereby the problem mentioned above can be eliminated. What is more specifically aspired to is an arrangement which affords better support for the frame side-members when the towing of a trailer subjects the towing vehicle to large laterally directed forces, and which occupies little space once it is fitted.
This object is achieved by the arrangement indicated in the introduction which is characterised in that the beam element, as seen in said longitudinal direction, extends in a direction which is at a substantial angle of inclination relative to said plane. By means of such a beam element extending obliquely upwards with respect to the frame side-members it is possible to absorb laterally directed forces which act on the frame side-members. A support contrivance with at least one such beam element need not be of any substantial extent in the longitudinal direction of the towing vehicle and can therefore be fitted in towing vehicles with little vacant space. For example, the support contrivance may be fittable substantially vertically above the tow beam.
According to one embodiment of the invention, the support contrivance incorporates a support element which is arranged at a distance from the frame side-members and to which said beam element is connected. Such a support contrivance may with advantage incorporate at least one column member connected to a second of the frame side-members and to the support element. Lateral rigidity is further improved by such a column member. The towing vehicle may have a body mounted on the frame side-members, and the support element connected to the body. At the same time, the support element may be connected to one or more different body parts, e.g. the rear wall of the towing vehicle, a floorboard for an internal space of the towing vehicle, etc. The support element may with advantage incorporate a top member which extends substantially parallel with said plane.
According to another embodiment of the invention, the support contrivance incorporates at least one connecting element and said beam element is connected to the first frame side-member via said connecting element. In this case said connecting element may incorporate a transverse member which extends outwards from the first frame side-member in a direction substantially parallel with said plane. Shifting the fastening of the beam element outwards makes it possible to achieve a favourable angle of inclination of the beam element. Said column member may also be connected to and extend from an outer end of the transverse member to the support element.
According to a further preferred embodiment of the invention the support contrivance incorporates two of said elongate beam elements each connected to its respective frame side-member. At the same time, the beam elements may with advantage extend symmetrically with respect to a central plane which is perpendicular to said plane. The beam elements may slope either inwards towards the central plane or outwards, and the two beam elements may with advantage be connected to the top member in a central region of the latter. The support contrivance may further incorporate two of said transverse members each extending outwards from its frame side-member, while each of the two elongate beam elements is connected to the outer end of its respective transverse member, and it may incorporate two of said column members each connected to the outer end of its respective transverse member and to a respective outer end of the top member.
According to a further preferred embodiment of the invention the towing vehicle is a bus and it has a drive motor for propelling it which is mounted at least partially between the frame side-members in the vicinity of the rear end of the towing vehicle ahead of the support contrivance and the tow beam as seen in the forward movement direction of the towing vehicle.
According to a further preferred embodiment of the invention the support contrivance and the tow beam are arranged removably on the towing vehicle in said rear end. The tow beam and the beam elements, column members and transverse members of the support contrivance are preferably detachably fastenable to the top member and the frame side-members respectively.